hypomyelinative neuropathy has a presentation in many ways similar to
Werdnig-Hoffmann disease. A sensory deficit is present but is usually
clinically undetectable in neonates. The first clue to the diagnosis of
hypomyelinative neuropathy is a very slow motor nerve conduction or the
presence of elevated cerebrospinal fluid protein in the presence of a
normal white blood cell count.
The diagnosis is established
by sural nerve biopsy. The biopsy shows little or no myelin sheath around
the axons and no evidence of demyelination or onion bulb formation in
sural nerve biopsy. This entity may occur sporadically or follow an autosomal
recessive or dominant pattern of inheritance. In most instances, this
disease is not progressive.
polyneuropathy or Guillain-Barre syndrome may occur in the neonatal period
and should be considered if a previously healthy neonate develops hypotonia
with decreased dynamic tone after an apparent viral illness. Cerebrospinal
fluid proteins are increased and motor nerve conduction is very slow after
2 weeks. These patients usually recover. This entity is very rare. Immunoglobulin
is the treatment of choice for acute polyneuropathy.
The effectiveness of immunoglobulin in the neonatal period is unknown.
Inflammatory Demyelinating Polyneuropathy
inflammatory demyelinating polyneuropathy presents very much like acute
polyneuropathy in a newborn. It is the history of chronicity or recurrence
as the patient gets older that raises the possibility of this diagnosis.
Nerve conduction is decreased. Nerve biopsy shows decreased myelin, evidence
of segmental demyelination and remyelination, and subperineural and endoneural
edema with inflammatory cells. The diagnosis is established by sural nerve
biopsy. Treatment with steroids is effective.